Abstract During the nineteenth century female Irish religious orders established missions across the Irish diaspora which were designed with flexibility and adaptation in mind. The Sisters of Mercy's personal letter networks allowed these women, who were often very young, to continue their religious and technical “apprenticeship” while abroad. These letters enabled women in the diaspora to maintain a sense of consistency and belonging across the oceans: with their sisters in Ireland and elsewhere in the world on an ethnic and institutional level. Engaging with these letters as both intimate conversations and professional reflections presents opportunities for investigating how long-distance institutional memory was developed and a continuing connection to Ireland and Irishness maintained. This article moves the focus of ethnic culture brokers from the priest and bishop to the formal and informal networks of women religious who worked within a system designed for men. In doing so, it demonstrates that these letters provided an important extra layer to public global Irish networks, a layer which acted as both a whisper network and an opportunity for reflection on efficient methods for varied work in large, fluctuating, and cross-class ethnic communities.